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powerpc: Use one common impl. of RTAS timebase sync and use raw spinlock

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Several platforms use their own copy of what is essentially the same code,
using RTAS to synchronize the timebases when bringing up new CPUs. This
moves it all into a single common implementation and additionally
turns the spinlock into a raw spinlock since the former can rely on
the timebase not being frozen when spinlock debugging is enabled, and finally
masks interrupts while the timebase is disabled.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
Benjamin Herrenschmidt
2009-06-16 16:42:50 +00:00
parent f97bb36f70
commit c4007a2fbf
5 changed files with 40 additions and 87 deletions
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31
arch/powerpc/kernel/rtas.c
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@@ -38,6 +38,7 @@
#include <asm/syscalls.h>
#include <asm/smp.h>
#include <asm/atomic.h>
#include <asm/time.h>
struct rtas_t rtas = {
.lock = __RAW_SPIN_LOCK_UNLOCKED
@@ -971,3 +972,33 @@ int __init early_init_dt_scan_rtas(unsigned long node,
/* break now */
return 1;
}
static raw_spinlock_t timebase_lock;
static u64 timebase = 0;
void __cpuinit rtas_give_timebase(void)
{
unsigned long flags;
local_irq_save(flags);
hard_irq_disable();
__raw_spin_lock(&timebase_lock);
rtas_call(rtas_token("freeze-time-base"), 0, 1, NULL);
timebase = get_tb();
__raw_spin_unlock(&timebase_lock);
while (timebase)
barrier();
rtas_call(rtas_token("thaw-time-base"), 0, 1, NULL);
local_irq_restore(flags);
}
void __cpuinit rtas_take_timebase(void)
{
while (!timebase)
barrier();
__raw_spin_lock(&timebase_lock);
set_tb(timebase >> 32, timebase & 0xffffffff);
timebase = 0;
__raw_spin_unlock(&timebase_lock);
}